The document discusses the proper use of "while" and "when" to describe past events. It explains that "while" is used to connect two continuous actions that happened simultaneously, and both actions should be in the past continuous tense. "When" is used to connect a longer action in the past continuous tense with a shorter action in the past simple tense, where one action occurred within the timeframe of the other. Examples are provided to illustrate the correct usage of "while" and "when" along with the appropriate verb tenses.

1. The use of when and while

2. While
• We use while to link two continuous
actions that happened at the same time
in the past.
• We use the past continuous tense for
both actions.

3. NOW
5:00 p.m. 8:00 p.m.7:00 p.m.
Tom and Mary were doing their homework.
Mum was cooking the dinner.
Tom and Mary were doing their homework
while Mum was cooking the dinner.
whilewhile

4. NOW
5:00 p.m. 8:00 p.m.7:00 p.m.
Tom was eating.
Tom was watching TV.
Tom was eating while he was watching TV.
whilewhile

5. When
We use when to link a long action and a
short action.
We use the past continuous tense for the
long action. We use the past tense for
the
short action.

6. NOW
5:00 p.m. 8:00 p.m.7:00 p.m.
Tim was doing his homework.
Mum came home at 6:30 p.m.
Tim was doing his homework
when Mum came home.
whenwhen

7. NOW
5:00 p.m. 8:00 p.m.7:00 p.m.
Tim was taking a shower.
The doorbell rang.
Tim was taking a shower when
the doorbell rang.
whenwhen

8. (draw a picture) (smile)
Two actions were happening at the same time in the past
John __________________________________________was drawing a picture while he was smiling.

9. (use the computer) (the computer break down)
A long action was happening and then a short action
happened in the past.
Mr.Lee ______________________________________
_______________________
was using the computer when the computer
broke down.

10. (Grandma fall on the floor) (Mary skip)
A long action was happening and then a short action
happened in the past.
Grandma ______________________________________fell on the floor when Mary was skipping

11. (The women chat)
(The man eat)
Two actions were happening at the same time in the past
The women _____________________________________were chatting while the man was eating.

12. Note:
e.g. 1. I was cooking dinner when I burnt my arm. 
2. I burnt my arm while I was cooking dinner. 
We can also use ‘while’ in the second sentence, but while
must be followed by past continuous tense.
I was cooking dinner while I burnt my arm 